There has been a continuing trend in electronics to reduce the size of information handling devices such as computers, calculators and the like. Computers for instance have in the last decade gone from desk top units to a size that will now fit in the palm of the hand. With this shrinking in size, information handling systems more frequently rely on batteries as a source of energy to power the component parts of the system. Reliance upon battery power creates a problem with respect to maintaining power to essential components of the system such as the memory.
Prior solutions to this problem produce incompatible trade offs. One solution has been to add an additional battery used solely for the purpose of maintaining power to the memory when the primary energy source is removed. This requires an increase in space and adds weight to the system which is generally undesirable in portable systems.
Another trend in the field of electronics has been to provide devices that operate at a much wider range of voltages than in the past. It is now common, for instance, to have memory devices that will operate within a wide range of voltages. In prior approaches, generally a single energy source would be provided to supply energy at the optimum or highest operating level of the device. This creates two problems for the designer. If the higher operating voltage is chosen, there will tend to be a decrease in battery life, whereas, if the lower voltage is selected, battery life is increased but performance is sacrificed.
Thus, a need has arisen for a method and apparatus for providing energy to an information handling system that overcomes these disadvantages.